Gem-polishing.



C. 1. COLEMAN.

GEM POLISHING. APPLICATIIOQ mm a0v.25. 1912.

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C. I. COlZEMAN.

GEM POLISHING. 7

APPLICATION HLED NOV-25, 1912. I

Patented Jan. 18, 1916.

3 SHEETS-SHEET 2.

C. J- COLEMAN.

GEM POLISHING.

APPLICATION men uov.25. 1912.

Patented Jan. 18, 1916 3 SHEETS-SHEET 3- I '5] "m wifor,

CLYDE J'. COLEMAN,

OF NEW ROCHELLE, NEW YORK, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO STERN-COLEMAN DIAMOND MACHINE COMPANY INC., A. CORPORATION OF NEW YORK.

GEM-POLISHING.

Specification of Letters Patent.

Patented Jan. 18 1916.

Application filed November 25, 1912. Serial No. 733,419.

To all whom it may concern:

Be it known that I, CLYDE J. COLEMAN, a citizen of the United States, residing at New Rochelle, in the county of lVestchester and State of New York, have invented certain new and useful Improvements Relating to Gem-Polishing, of which the following is a specification, reference being had therein to the accompanying drawings, forming part thereof.

My invention relates to the art of polishing diamonds and relates more particularly to locating the grain of the diamond.

Objects of my invention are to enable the finding of the grain quickly and accurately, economizing time and labor, and also eliminating to a large extent the necessity for great skill in manipulation.

It has long been known that to secure effective results in polishing a facet on a diamond, the diamond must come in contact with the polishing lap in such a position that the traveling or polishing movement of the lap on the diamond will take place in the direction of the grain of the diamond at that point? Heretofore, this positioning of the'diamond on the lap has been dependent upon the skill of the operator to find the position in which themost effective polishing would take place, and even with the greatest of skill, sometimes several trial posi tionings have to be made.

My present invention lncludes broadly means for taking cognizance of the differences in physical effects produced by different rotative positions of a diamond when the diamond is rotated on an axis perpendicular to a movable friction surface with which the diamond is held in contact. The results due to the differences in physicaleffects produced may be immediately indicated and observed, and may also be recorded whereby the grain is indicated hefore any material abrasive action may have taken place on the diamondby the friction surface. As examples of the different physical effects which may bentilized or taken advantage of to ascertain the grain of a diamond may be mentioned: First, by vari ation in frictional resistance produced; second, by variation in temperature produced; third, by differences in luminous or sparks ing effects; fourth, by differences in sound produced; fifth, by diiferencesin intensity of static electricity produced. In its broader aspect the invention includes the determination of the grain by utilizing any specific. physical effects such as above mentioned. More particularly the invention isdirected. to the utilization of the first mentioned physical effect, namely, frictional resistance, and also to the'illustrated means for carrying out the present invention.

Two embodiments of the present invention are .illustrated in the drawings, that illustrated in Figures 1, 2, 3, and 4, being adapted to. both visually indicate and to record the variations in frictional resistance, produced on the friction surface of a friction member by the diamond in different r0- tative positions of the diamond, and the other, illustrated in Fig. 5, being adapted to visually indicate, without recording, the rotative position of the diamond corresponding to the grain as desired to be ascertained for polishing the diamond. In either case,

the determination of the grain enables the I diamond to be accurately positioned in .accordance therewith on the polishing lap for effectively polishing or producing the facets.

I shall now describe the grain finding machine embodying my invention illustrated in the accompanying drawings and shall thereafter point out my invention in claims.

Fig. 1 is a side elevation, partly in section, of a grain finder embodying my invention in one form. Fig. 2 is a detail of the electric circuit employed in the grain indicating and recording mechanism of the grain finder. Fig. 3 is a plan of thegrain finder. Fig. t-is a horizontal section on a seen from above. Fig. 5 is a side elevation of a modified construction of grain finder.

In the grain finder illustrated in Figs. 1 to 4, inclusive, of the drawings, a small size preliminary polishing disk or lap 1 is provided for starting the facet previously to locating the grain, that is to say, a small facet or small plane surface is first formed on the generally rounded orsharp edged surface of the bruted diamond. This small facet is only of sufficient size for use in determining in which direction the grain of the diamond runs in respect to this preliminary small facet. After the direction of the grain has been determined, then this is taken advantage of in posi- ,plane indicated by line 4-4! of Fig. 1, as p I asto finally most effectively form the complete facet; The small or preliminary-lap '1 is rotatively fixed on an arbor 2, which is shown, as adapted to be directlyrotated by means of an electric motor 3 of which the arbor 2 forms a continuation of the armature shaft, the motor 3 being mounted on p the frame of the grain finder.

The small preliminary lap 1 is surrounded by the plane annular friction surface of a grain finding friction member4. The fricti'on member 4 is arranged concentric with the preliminary lap 1 and is rotated by the arbor 2 by means of a yielding resilient connection, shown as a coiled torsion spring 5 anchored at its upper end to the friction memher 4, and at its lower end to a driving disk 6 fixed on the arbor 2.

To increase the sensitiveness of the yielding connection between the arbor 2 and thefriction member 4 ball bearings are interposed,as shown in Fig. 1. The torsion spring 5 measures the frictional resistance to which the friction surface of the friction membar 4' is subjected. Any change or variation in friction on the friction surface of the friction member 4, will result in correspond ing changes in rotativev position of the friction member relatively to the arbor 2.

The sliding friction of a friction surface in contact with a diamond is greater in-"the'direction of the grain of the diamond, and if the diamond be slowly rotated on an axis perpendicular to a traveling friction surface-with which the diamond is in sliding contact, the

frictional resistance between the diamond and the'friction surface will increase each time the diamond. comes into a position so that the direction of the sliding'movement.

corresponds with the'directionof the grain of the diamond. From the foregoingfact,

it follows that if a diamond be held in coni tact with-the'plane annular friction surface I face, the friction member 4 will periodically of the friction member 4 and be rotated on an axis perpendicular-to s'u'ch friction surlag in its rotation, or rotatively shift its position in reference to the arbor 2, the

periods of laggingmovementcorresponding to'the-periods of frictional contact in which .the sliding movement takes place in thedirectionof the grain of the diamond.

In carrying out my invention means are.

provided for holding and rotating 9. diamond in the manner described and also means are provided for indicating andrecording variationsin the torque. required to rotate the sensitive friction member 4. In the present machine for finding the grain of diamonds .the same diamond holding head is employed to hold the diamond on the preliminary lap 1, and on the friction member 4, the diamond preferably being rotated on an axis perpendicular tothe preliminary lap 1, during the formation of the small initial facet, such rotation of the diamond enabling the grain of the diamond to be taken advantage of periodically during each rotation of the diamond, for more expeditiously forming the small facet.

It should be here noted that the diamond holding head of the present machine, in cluding the means for rotating a diamond relatively toa polishing lap while forming a facet, means for adjusting the diamond about its geometric center, and also other features, is made the subject of a separate.

application for patent filed on even date herewith, Serial Number 733,417, and the cooling means herein disclosed is made the subject of another patent application, filed July 20th,1912, Serial Number 710,623, for

Means for holding diamonds abrasive treatment.

The diamond holding'head will now be sufficiently described for the purposes of the present invention. The holder head for the diamond has a vertical main shaft 7, journaled for rotation and also forfree limited vertical movement in a journal block 8,

adjustably and removably mounted on a horizontal upper arm 9 of the machine frame. 'The journal block 8'is held in place on the supporting arm 9 by a clamp bar. 10, controlled by a wing nut 11. An arcuate during I arm 12 isadjustably carried by the lower 1 end of the supporting shaft 7 and provides for the adjustment of the diamond about its geometric center for forming the facets, in

the different concentric rows of facets at one" side of the girdle. A dop holder 13 is car ried by one end of the arcuate arm 12 and I supports a drop having a head 14 anda supporting stem'15. The'dop is rotatively ad-' cooling means as'indicated by the conduits conduit 18 being flexible to ment of the arcuate arm 12, I I

The diamond 16 is shown in the drawings as presented'to the preliminary lap 1 for forming an initial facet-on thediamond. 1 To permit adj u'st- 17 and 18 for supplying a cooling fluid, the.

present the diamond 16 to the friction surface ofthe friction member 4 for determining or locating the grain of the diamond,

block 8 is slipped along the supporting arm tightened. .The vertical shaft 7 and the parts carried thereby, including the dia- --.the clamp 10 i released and thejournal 9 to theproper place and the clamp 10 again I mond .16, may be rotated by means of a worm fwheel 19 fixed on the shaft 7, and enof the diamond holding head above mentioned. The counter shaft '21 is adapted to be rotated by an electric motor 22, connected to the counter shaft 21 by means of a worm 23 fixed on the armature shaft of the motor and meshing with a worm gear -24 fixed on the counter shaft.- By means of the speed reductions from the two sets of worm gears, a comparatively slow speed of rotatlon w1ll be given to the vertical shaft 7 which directly rotates the diamond 16.

The means provided for, indicating and recording the variations in the torque required to drive the sensitive friction member 4 in the different rotative positions of the diamond 16 will now be described; The disk 6, which carries the lower end of the torsion spring 5, is composed of insulating material, as indicated in Fig. 1, and a'split. graphite resistance ring 25 is carried by the disk 6 on its upper side. A contact brush 26 is coiiperative with the resistance ring 25 and is'carried by the lower end of a sleeve portion of the friction member 4, this sleeve portion being. shown as surrounded by the .coiled torsion spring 5. A stop pin 27 (Fig. 4) is provided on the disk 6 for the brush 26, this stop pin being located at a point so' that the brush 26 will make contact with the resistance ring 25 just at one side of the split or division in such ring, and so that as a the spring is put under, tension by the driving torque applied to the friction member 4, the brush 26 will travel around the resistance ring 25 in a direction away from the division or split therein. One end of the resistance ring 25 is electrically'connected througha conductor 28 with acontact ring 29 which is insulated from the arbor 2 by an insulating sleeve 30 (Fig. 2). A

brush 31 cooperates with the insulatingring.

29 and a conductor 32. connects this brush with a battery The electric circuit is adapted to be completed from the battery 33- through a conductor 34, through the coil of an electrical measuring instrument 35, a conductor 36, a circuit closer 37, a conductor 38, a brush 39, and a groundedcontact ring 40 which is carried'by and is in electrical connection with the arbor ,2.

' .From the preceding explanation of the construction, it will be understood that any movement of the frictlon member 4 relatively to the arbor 2 will cause the contact brush 26 to travel over the resistance ring 25 and will accordingly-wary the resistance included in the electricycircuit in which is included the electrical measuring instrument l a I that of a polishing lap.

35, and will cause rotative movement of the pivoted armature coil of such instrument. This coil is shown as mechanically connected by means of a crank 41 and a link 42 with a marker 43. The marker 43 is cooperative with a dial 44, rotatively carried by the upper end of the vertical shaft 7 of the diamond holding head.

In the operation of the grain finding machine, the diamond is first applied to-the rapidly rotating preliminarylap 1, as shown in Fig. 1, and, for effective operation in forming a preliminary facet, the diamond is slowly rotated on an axis perpendicular 'to the lap 1, by means of the electric motor 22,

the diamond being pressed against the I abrasive surface of the lap by reason of the weight 'of the-diamond holding head.

Wherithe preliminary facet has been.

formed, the diamond holding head is shifted along the supporting arm 9 to bring the diamond into contact with the friction surface of the sensitive friction member 4, upon the friction surface of which the diamond will be held with a uniform pressure. This shifting of. the diamond holding head also brings the dial 44 into cooperative relationship with the marker 43. The diamond holding head will now slowly rotate the diamond in contact with the rapidly moving annular "friction surface of the friction member 4. The torque required to rotate, the friction member 4 will be measured by the torsion spring 5, and as the torque varies, due to the different rotative positions of the diamond in reference to its grain, the brush 26, moving over the resistance ring 25, will Vary the resistance included in strument 35, and will cause the marker 43 to be actuated to produce a record on the .dial 44. Becauseof the fact that the dial 44 rotates in unity with the diamond, the record made on the dial will directly indicate the grain of the diamond and may be used as a guide in placing the diamond on the polishing lap. When the grain for any particular facet has been located, the entire diamond holding head, including the removable journal block 8, maybe removed The modified construction illustrated in Fig- 5'embodies a simplified form of the invention.- In this construction a small polishing lap 45 is adapted to be rotated by a light power series wound-electric motor 46 the circuit with the electrical measuring inwhich is very delicately responsive to-load variations. The circuit of this motor includes a current meter 47 included in the circuit in series. When, as in the first instance, a diamond in contact with the rapidly rotating lap 45 is slowly rotated on a indications of the ammeter in the different rotative positions of the diamond will en- 1 able the diamond-carrying holder head. to

be-lifted from the grain finding machine and correctly positioned on a polishing lap.

It is obvious that various modifications "may be made in the constructions shown in the drawings and above particularly described, within the principle and scope of my invention.

I claim:

1. A machine for locating the grain of a diamond comprising a friction surface, means for holding a diamond in contact with such surface, means'for producing relative traveling movement between 'the'fricti on surface and diamond in the plane of the friction surface at its point of contact with the diamond, and means for taking cognizance of differences in physic'aleifects produced in the different rotative positions of thediamond when rotated about an axis perpendicular to said friction surface.

2. An arrangement of the class described havingin combination a relatively movable friction surface, means for rotating the facet of a gem upon said surface, and indicating mechanism immediately responsive to differences-in the physical effects produced as the facet is rotated, substantially for the purpose specified.

\ 3, A machine for locating the grain ofv a diamond comprising a friction surface, means for holding a diamond in contact with such surface, means for producing relathe diamond therewith, and means for measuring the frictional resistance produced be-. tween the diamond and the friction surface by the traveling movement while the rotary movement is also taking: place.

4.,A machine for locating the grain of a diamond, comprising a rotative friction member provided with a friction surface, means for holding the diamond in frictional contact with the friction surface at an eccentricpoint on the friction member, means for rotating the friction member, means for rotating the diamond on an axis perpendicular to the friction surface at the point of contact of the diamond therewith, and means for indicating the torque required to rotate the friction member in the difierent rotative positions of the diamond relative to the fric- I tion member.

5. In an apparatus of the class described, means for holding a diamond, a suitable surface in engagement therewith, means for moving said surface relatively to the diamond, and means for taking cognizance of diflerences in physical effect produced with the diamond in different rotative positions about an aziis perpendicular to said surface.

6. A machine for locating the grain of a diamond comprising a rotative frictionmember provided with a friction surface, means for holding the diamond in frictional contact with the friction surface at an eccentric point on the friction member,

means for rotating the friction member, 2

means for rotating the diamond on an axis perpendicular to the friction surface at the point of contact of the diamond therewith,

for rotating the friction member and such member for permitting the friction member to rotatively yield relative to its rotating resilient means connected between the means means, and electrical means for indicating I the extent of yielding in the resilient means corresponding to difierent rotative positions face, driving means for rotating the friction i member, a torsion spring interposed in the driving connections between the driving means and the friction member for permitting the friction member to rotatively yield relative to the driving means, a variable resistance rotatively carried by the driving means, a movable contact member rotatively carried by the friction member and engaging the variable resistance, anelectric circuit including the. movable contact member and the variable resistance, a source of electric current included in the circuit, an eleotrical measuring instrument included in the circuit, means for holding a diamond in contact with the friction surface of the friction member, and means for rotating the diamond on an axis perpendicular to the fricing instrument will indicate thef'drivin'g' torque of the friction member in different rotative positions of the diamond-on the the grain of the diamond.

,tion surface, whereby the electrical measurfriction member and will thereby determine.

, 8. A machine for locatingthe grain of a diamond comprising a ,rota'tive friction member provided with a friction surface,

means for holding the diamond in contact with the friction surface, means for rotating the diamond on an axis perpendiculanto the frlction surface at the point of contact, of,

the diamond therewith, driving means for rotating the frictionmember, resilient means connected' between the driving means and the frictionmember for permitting the friction member to rotatively shift relatively to thedriving means therefor, a record blank arranged to be moved in harmony with the rotation of the diamond, a marker cooperative with the record blank, and mechanism for communicating the rotary shifting movement of the friction member relatively -to its driving means to the marker for recording on the record blank the varying amounts of friction between the diamond and the friction member in different rotative positions of the diamond relative to the friction member.

9. A machine for locating the grain of a ,diamond comprising a rotative friction member with a plane friction surface, means for holding the diamond contact with the friction surface, means for rotating the-diamond on an axis perpendicular to the fric-' tion surface, a dial mounted to rotate with the diamond, driving means for rotating the friction member, a torsion spring interposed in the'driving connections between the driving means and friction member for permitting the friction member to rotatively shift relatively to the driving means, a split resistance ring rotatively carried by the driving means, a contact brush rotatively carried by the friction member and engaging the resistance ring, an electric circuit including the contactbrush and the resistance ring, a source of electric current included in the circuit, an

electrical measuring instrument also included in the circuit and having a pivoted indicating shaft, and a marker actuated by the indicating'shaft and cooperating with the dial. Y

1,0. A grain finding machine for locating the grain of a diamond comprising a polvishing lap, an arbor on which the lap is fixed .for rotation with the arbor, driving means for rotating the arbor, a rotative frictionmember mounted for rotative movement on the arbor and having an annular friction surface concentric with the lap, resilient .rotatively yielding driving connections between the arbor and the friction member, a rotative dop holder for holding the diamond, the dop holder and the arbor being relatively adjustable so that the dop 1 transmitting the rotation of the friction member relatively to the arbor to the marker, whereby variations in friction of the diamond with the friction member for difierent rotative positions of the diamond will be recorded on the dial.

Intestimony whereof I have affixed my signature in presence of two witnesses. CLYDE J. COLEMAN.

Witnesses: i

, Vro'ron D. Boner, WM. A. KELLY. 

